---
name: "ng_device"
section: "4"
platform: "linux"
package: "freebsd-manpages"
version: "6.0-5"
release: "Debian 4.0 (Etch)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/ng_device"
---

# ng\_device(4)

device netgraph node type

## NAME

**ng\_device** – device netgraph node type

## SYNOPSIS

**#include \<netgraph/ng\_device.h\>**

## DESCRIPTION

A **device** node is both a netgraph node and a system device interface. When a **device** node is created, a new device entry appears which is accessible via the regular file operators such as [open(2)](/open/2.md), [close(2)](/close/2.md), [read(2)](/read/2.md), [write(2)](/write/2.md), etc.

The first node is created as */dev/ngd0*, all subsequent nodes */dev/ngd1*, */dev/ngd2*, etc.

## HOOKS

A **device** node has a single hook with an arbitrary name. All data coming in over the hook will be presented to the device for [read(2)](/read/2.md). All data coming in from the device entry by [write(2)](/write/2.md) will be forwarded to the hook.

## CONTROL MESSAGES

The **device** node supports one non-generic control message:

- NGM\_DEVICE\_GET\_DEVNAME

  Returns device name corresponding to a node.

## SHUTDOWN

This node shuts down upon receipt of a NGM\_SHUTDOWN control message, or upon hook disconnection. The associated device entry is removed and becomes available for use by future **device** nodes.

## SEE ALSO

[netgraph(4)](/netgraph/4.md), [ngctl(8)](/ngctl/8.md)

## HISTORY

The **device** node type was first implemented in FreeBSD 5.0.

## AUTHORS

Mark Santcroos ⟨marks@ripe.net⟩ Gleb Smirnoff ⟨glebius@FreeBSD.org⟩